To meet the varying cooling and/or dehumidifying load of a comfort zone, some HVAC refrigerant systems might include a system component of adjustable capacity. Examples of adjustable capacity components include compressors, indoor evaporator fans and outdoor condenser fans.
U.S. Pat. No. 5,303,561 discloses adjusting the indoor fan speed to meet the latent cooling needs of a comfort zone. U.S. Pat. No. 4,590,772 suggests varying the draft volume to a condenser based on the refrigerant pressure therein. U.S. Pat. No. 5,062,276 discloses a refrigerant system where the fan speed is varied linearly with compressor speed, and their speed relationship is altered in response to the need for dehumidification. U.S. Pat. Nos. 5,305,822; 5,345,776; 5,426,951 and 6,826,921 disclose varying the speed of an outdoor fan. And U.S. Pat. No. 6,223,543 discloses varying the speed of an indoor fan.
Although adjusting the capacity of a single component might be relatively straightforward, it can be challenging to control a refrigerant system that includes more than one component of adjustable capacity because varying the capacity of one component can affect the performance of another.
Consequently, there is a need for a refrigerant system that provides a method of adjusting and coordinating the variable capacities of multiple, interrelated components of the system.